Telefonica Research at CHI ’14

Telefonica Research will be represented with 2 full papers and 2 ToCHI articles at ACM CHI ’14, the premier international conference of Human-Computer Interaction.

Didn’t You See My Message?

Martin Pielot, Rodrigo de Oliveira, Haewoon Kwak, Nuria Oliver

We found that monitoring the phone (screen activity, notification center access, proximity sensor, ringer mode) allows to predict whether a person will attend to a received message fast or not (pdf).

A brief but more detailed description can be found in in more recent blog post.

Large-scale assessment of mobile notifications

Alireza Sahami Shirazi, Niels Henze, Martin Pielot, Dominik Weber, Albrecht Schmidt

As part of the study, we published an Android app on Google Play that forwards all phone notifications to the browser (via plugin). More than 40,000 people thought this was a brilliant idea and downloaded the app. We used the app as a vehicle to log and analyze all notifications that users receive (pdf).

A Large-scale Study of Daily Information Needs

Karen Church, Mauro Cherubini, Nuria Oliver

My colleagues have conducted one of the most comprehensive studies of information needs to date. For three months, they probed information needs via experience sampling and daily diaries, to understand “the types of needs that occur from day to day, how those needs are addressed and how contextual and demographic factors impact on those needs” (details on Karen’s website.)

Influence of Personality on Satisfaction with Mobile Phone Services

Rodrigo de Oliveira, Mauro Cherubini, Nuria Oliver

My colleagues connected the phone use habits of 603 volunteers with personality traits and customer satisfaction, and found that “(1) extroversion, conscientiousness, and intellect have a significant impact on customer satisfaction—positively for the first two traits and negatively for the latter; (2) extroversion positively influences mobile phone usage; and (3) extroversion and conscientiousness positively influence the users’ perceived usability of mobile services” (ACM Digital Library).

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October 26, 2013February 6, 2015

Open CSV files by double click with Excel 2011 (OS X)

Excel can open and interpret CSV files on double click.

However, for some locales it may happen that all the content appears in the first row.

This is how I fixed it.

Clean up Preferred Languages

In my case, I am using Excel 2011 for OS X 10.9. The CSV was not interpreted correctly, because German appeared in the Preferred languages of the Language & Region settings.

The simple fix was to remove all preferred languages except from English (United States) so that it would become the primary language, and then re-add the other languages.

After that, Excel 2011 flawlessly opened a comma-separated CSV file on double click and distributed the values correctly over the rows.

Background

German, and other languages, use the comma instead of the dot as decimal separator (e.g. 123,45 instead of 123.45). Thus, Excel on German machines expects semicolons to separate values in a CSV file. The fix above will help to work with CSV files in international environments.

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September 3, 2013February 6, 2015

Ambient Timer – Unobtrusively Reminding Users of Upcoming Tasks with Ambient Light

Alice is working on a report for the head of her department. At the same time, there is a meeting scheduled in thirty minutes, which she has to attend. The Ambient Timer is already illuminating the wall behind her monitor in a low-attention state, so Alice feels confident that she will be reminded of the meeting. A few minutes before the meeting, the status of the ambient light display has changed to a more salient, intense output. While she is still working on her report, she slowly becomes aware of the nearing deadline and starts finishing the paragraph she is currently working on. One minute before the meeting the light has become so salient that it is hard to ignore. Alice stores the document on the server, puts her computer into sleep mode, and arrives at the meeting on time.

A timer that uses ambient light

The Ambient Timer is a research prototype developed in the Interactive Systems Group of the OFFIS Institute for Information Technology. Its goal is to gently remind information workers about upcoming events. such as illustrated in the scenario above. It uses LED glued to the back of the monitor to illuminate the wall in the peripheral field of vision of the worker.

User Study

With this prototype, we conducted a user study in collaboration with the HCI and Mobile Computing Group of Telefónica Research. We experimentally studied two instances of the Ambient Timer:

expo: a gradual change from green to red, becoming exponentially faster, and
sinus: a sinusoidal change between red and green which became increasingly faster.

We compared these reminders against two traditional techniques to keep track of appointments:

a clock, such as the one in the corner of your computer screen, and
a popup alarm, such as when you use Outlook, Lotus Notes, or the OS X Calendar for your appointments.

For the study, we asked participants to copy and correct texts. Meanwhile, a 10-minute timer was running in the background. The task was to finish as many texts as possible in 10 minutes, but without “overshooting”, i.e. having an unfinished text after 10 minutes. In the expo, sinus, and clock conditions, the remaining time was presented by the Ambient Timer or a clock, respectively. In the popup condition, no time was given, but a popup informed the participants 30 seconds before the end of the time limit.

The experiment used a repeated-measures design, i.e. each participant tested each of the four reminder systems in counter-balanced order.

Results

Our results show that participants experienced significantly fewer interruptions when using Ambient Timer in the expo condition, i.e. with an exponential change from green to red, compared to all other reminder techniques in our experiment. Their average typing speed was significantly faster when in this condition, too. Participants ranked this design best, felt most confident using it and preferred it over all other techniques.

Conclusions

This experiment shows that using light in the periphery around the monitor is a great way to provide information workers with information in an ambient way. Used as Ambient Reminder, ambient light might help to structure typical office work, which is often a mix of concentrated desktop work and scheduled meetings and appointments. It allows office worker to avoid to constantly check the clock or be interrupted by alarming popups interrupt.

Publication

The details of the experiment have been published in the 14th IFIP TC13 Conference on Human-Computer Interaction, held in September 2013 in Cape Town, South Africa:

Heiko Müller, Anastasia Kazakova, Martin Pielot, Wilko Heuten and Susanne Boll.
Ambient Reminder: Unobtrusively Reminding Users of Upcoming Tasks with Ambient Light.
INTERACT ’13: 14th IFIP TC13 Conference on Human-Computer Interaction, 2013.

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August 28, 2013February 6, 2015

Peripheral Vibro-Tactile Displays

If you are sitting, which parts of your body are currently touching the chair? Are you leaning on a backrest or an armrest?

Think about it! Now, you are aware! But have you been just before reading this post? Probably not!

This is the beauty of peripheral perception, i.e. perceiving sensory input in the periphery of our attention. Your brain perfectly knows how to process the touch input it gets from the different parts of your body so that you do not fall of the chair. At the same time, you can perfectly focus on reading this text.

Using our Sense of Touch for Periperphal Communication

But, could this property of our sense of touch also be used to communicate information in the periphery of attention via mobile and ubiquitous computing devices? For example, imagine a bracelet indicating the time remaining until your next appointment, or your mobile phone indicating that there are no unread emails, messages, or social network updates to attend to.

Peripheral Vibro-Tactile Displays

In our research on peripheral, vibro-tactile displays, we made first investigations to prove that such information presentation could be possible with vibration motors, or vibro-tactile displays, as they can be commonly found in our mobile phones.

Study: Exposing People to a Constant Heartbeat

15 participants wore a vibro-tactile display in their pocket for 3 days. The display was set to create a constant, soothing, heartbeat-like vibration pattern. Via mobile phone, the participants adjusted the intensity, so that the vibration was barely perceptible.

Death Events: Testing Awareness

To test whether the vibration was still perceived, it died after 15 to 60 minutes. As soon as the participants noticed, they had to acknowledge the death of the vibration by pressing a button on a mobile phone. In the study, the majority of the death events were noticed between 1 and 10 minutes after the vibration had died. This is an indicator that participants were still aware about the vibration, even though it was set to very low intensities.

Testing Ambientness

To check whether the vibration had left the participants conscious perception, i.e. the focus of attention, we opened a questionnaire on the phone once the participants had pressed the button. In 67.7% of the cases, the participants indicated that the subjectively did not think that they had noticed quickly that the vibration had died. Additionally, in 94.4% of the cases, the participants reported to not be annoyed by the vibration. These two results indicate that the heartbeat vibration was indeed not in the focus, but in the periphery of attention.

Conclusions

These results provide first evidence that vibration patterns can form non-annoying, lightweight information displays, which can be consumed at the periphery of a user’s attention.

However, these findings are only first steps. We need more evidence to back up the findings, and we need more insights into how to adjust the intensity of the vibration pattern to different situations, so that we always hit the sweet spot of being just barely perceptible.

Publication

The details of this study will be presented at ACM MobileHCI ’13, the 15th International Conference on Human-Computer Interaction with Mobile Devices and Services, held in August 2013 in Munich, Germany.

Martin Pielot and Rodrigo de Oliveira.
Peripheral Vibro-Tactile Displays.
MobileHCI ’13: 15th International Conference on Human-Computer Interaction with Mobile Devices and Services, 2013.

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August 25, 2013September 2, 2013

iPad 4 or iPad Mini?

Planning to buy an iPad?

If you are thinking to join the Apple world of tablet computers, you probably have already thought about whether it should be a Mini or a ‘regular’ iPad.

In this article, I give some potentially helpful information for your choice: I present my personal experience owing both devices.

My Experiences

The iPad is regularly use are a 16GB iPad 4 with WiFi only, and an iPad Mini with16GB + 3G/GPS module. My analysis is therefore based on these devices.

First of all, the iPad Mini is indeed “every inch an iPad“. If you are using the iPad Mini, you won’t notices that anything is missing. All iPad apps run perfectly. Even Siri is available. And, surprisingly, despite the smaller screen, it never feels too small.

Handling is where the iPad Mini shines. Its reduced size and weight will come in handy in many situations:

You can hold it in one hand for a long time without getting tired. The iPad 4, in contrast, quickly starts feeling heavy, thanks to the bigger battery required for the retina display.
When writing notes, an email, or a message, the size factor clearly favours the iPad Mini. It’s much easier to hold it with two hands and use the two thumbs for writing – they will much easier reach those keys that are in the middle of the screen.
Because it’s lighter and smaller, you will more often find you taking it on your trips. Therefore, you can use it in more situations, which will make it more useful – in particular if you invest into a 3G / GPS upgrade.

Graphics is where the iPad 4 shines. It’s retina display provides an amazing viewing experience. The screen is far more crisp. Once your eye got used to the 264 pixels per inch (ppi), other displays start to look disappointing. Also, when running apps for the iPhone in double-size, the iPad 4 displays them much smoother than the iPad Mini.

Regarding processing speed, the iPad 4 features a faster processor. If you put both devices next to each other and start an activity on both devices at the same moment, you will see that the iPad 4 is a tick faster than the iPad Mini. However, during normal use you will never think that the iPad Mini is slow. The iPad 4’s A6X processor with quad-core graphics might come in handy for hardcore games, but I haven’t yet felt a significant performance difference.

The amazing display of the iPad 4 come with a caveat: it requires a lot of energy, which in consequence creates a lot of heat. You will find the iPad 4 becoming hot much more often than the iPad Mini.

Conclusions

The decision strongly depends on what is important for you. I would slightly favour the iPad Mini, since all-in-all it’s more useful due to its form factor. However, if your main use for the iPad will be the couch, the iPad 4’s retina display makes it the better choice.

Of course, these are all my personal experiences and opinions. For your specific case, other factors might be more important. Yet, The conclusion matches with the reviews appeared on About.com, The Telegraph, and ZDNet.

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July 14, 2013February 6, 2015

I Never get the Good One’s! How many Paper to Review?

“I never get the good papers for review.“

If this thought has ever crossed your mind, you are probably not alone. Good conferences in the HCI field typically accept only 20-25% of the papers submitted for review.

So how many papers to accept for review

… to review at least one good one?

It may seem obvious: the number should depend on the acceptance rate of the conference: 4 papers for 25%, 5 papers for 20%, 6 papers for 16.6%.

So, you are doing this already, and you still seem to get only the to-be-rejected ones?

This is, because probability computation does not always follow the intuitive approach.

Compute by rejection rate

The key is to compute by rejection rates and multiply them per paper.

If you review one paper from a conference with 20% acceptance rate, it’s likelihood to be rejected is 80%.
For two papers from the same conference, the likelihood that both are rejected is 80% * 80% = 64%. (not 60%, as what our intuition might tell us)

The row continues:

three papers = 51.2%
four papers = 41.0%
five papers = 32.8%

So, even if you review five papers in this conference, the likelihood is 32.8% that all of them will be rejected.
See the diagram below for different acceptance rates (25%, 20%, 15%).

Likelihood of Reviewing Accepted Paper by Acceptance Rate of a Conference

So, how many papers to accept for review?

If you want to have a ~~20%~~ 80% chance of reviewing at least one accepted paper, you have to accept the following number of papers for review:

6 papers for a venue with a 25% acceptance rate
7-8 papers for a venue with a 20% acceptance rate
10 papers for a venue with a 15% acceptance rate

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June 22, 2013February 6, 2015

Use 18pt Font Size for Readers with Dyslexia

Dyslexia: a common reading disability

Dyslexia is a neurological reading disability, which impairs a person’s ability to read and write. In the media, we often hear about dyslexia as a gift in the context of famous people, such as Steve Jobs. However, in reality, depending on the language, a significant chunk of the people suffer from dyslexia, e.g. 10 to 17.5% in the US. For most of these, dyslexia is not a gift: the most common way of identifying dyslexia in children is bad performance in our reading-centric education system.

Can the right presentation parameters improve reading?

The good news is that reading increasingly takes place via electronic displays, where we can adapt the presentation of text to make it easier to read for people with dyslexia. Therefore, led by Luz, we (Luz Rello, Martin Pielot, Mari-Carmen Marcos, and Roberto Carlini) set out to find optimal values for the most simple parameters of presentation: font size and line spacing.

Eye-tracking study exploring font size and line spacing

The study was conducted by Luz Rello in the Universitat Pompeu Fabra (UPF) in Barcelona, Spain. 28 people (15f, 13m), aged 14-38, with a confirmed diagnosis of dyslexia took part in the study. They were asked to read Wikipedia articles that were presented with different font sizes and line spacings. The study used eye tracking and questionnaires to measure readability and comprehension.

The experiment compared:

Font sizes: 10, 12, 14, 18, 22, and 26 pt.
Line spacings: 0.8, 1.0, 1.4, and 1.8.

Findings

To make a long story short, line spacing did not have much of an impact. Only 1.8 line spacing lead to worse comprehension compared to 0.8 line spacing.

Regarding font size, however, the results were surprising. When we look for optimal font size in the web, we either find soft recommendations, such as “allow to adjust”
or values around 12pt / 14pt.

However, our results provide strong evidence that for people with dyslexia, readability and comprehensibility of a text increases with font size, which an optimum around 18pt.

In particular, we found that:

The objective readability, which is indicated by the fixation duration recorded with the eye-tracker, steadily increased until 18pt.
The subjective readability was highest for 18pt and 22pt.
The subjective comprehensibility was highest for the three largest fonts: 18pt, 22pt, 26pt.

Conclusions: use 18pt font size for your website

Hence, when designing a website that shall be friendly to readers with dyslexia (remember, 10-17.5% of the population!), use large fonts. Since there was no improvement at larger font sizes, 18 pt font size hits the sweet spot.

Complete report

The complete scientific report can be found below.

Luz Rello, Martin Pielot, Mari-Carmen Marcos and Roberto Carlini.
Size Matters (Spacing not): 18 Points for a Dyslexic-friendly Wikipedia.
W4A ’13: 10th International Cross-Disciplinary Conference on Web Accessibility, 2013.

This work was published at the 10th International Cross-Disciplinary Conference on Web Accessibility, held 13-15th May 2013 in Rio de Janeiro, Brazil.

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December 11, 2012February 6, 2015

How the Phone’s Vibration Alarm can help to Save Battery

“Not sure how long my hero’s battery will last with GPS on and my phone vibrating every second to indicate if on right track!?!”

– This and similar concerns have frequently been expressed when I presented the PocketNavigator – a navigation system guiding pedestrians by vibration patterns instead of spoken turning instructions.

To quantify how much battery power is actually lost to constantly repeated vibration pulses, I tested the battery consumption of two different patterns in comparison to a non-vibrating phone.

In brief, in my setup, the vibration cost less than 5% of the battery life. As comparison: leaving the screen on will drain the phone’s battery in 2-3 hours. In consequence, instead of draining the battery fast, vibration can even help to save battery if it allows users to leave the screen turned off.

Test Configuration

The apparatus created heartbeat-like vibration patterns, i.e. patters consisting of two pulses followed by a long pause. The apparatus was run three times. Each run used a different pulse length, i.e. 30 ms, 60 ms, and 0 ms (no vibration as baseline).

Results

The following diagrams show the remaining battery as it changed while the app was running.

The battery lasted

24.71 hours for 0 ms pulse length (baseline)
23.48 hours for 30 ms pulse lengths = 95.0 % of the baseline, and
23.48 hours for 60 ms pulse lengths = 95.0 % of the baseline.

Using linear approximation to account for the fact that the battery was never 100% charged when the trials commenced, we also calculated the trend lines (see Diagrams, used Excel’s linear approximation), which changes the prediction to

24.18 hours for 0 ms pulse length (baseline)
23.28 hours for 30 ms pulse lengths = 96.3 % of the baseline, and
23.60 hours for 60 ms pulse lengths = 97.6 % of the baseline.

Discussion

Battery life in all cases was around 24 hours, sufficient for normal use. Constant vibration reduced battery life by 2.4 – 5.0 % minutes. Increasing the vibration length from 30 to 60ms per vibration pulse had no effect on battery life. As comparison, when the screen is constantly kept on, the battery drains within about 2-3 hours.

Hence, the additional battery loss is justifiable when considering that at the same time we gain the ability to continuously communicate information to the user. When using short vibration pulses, desigers do not even have to consider the effect of the pulses’ lenghts on battery life.

Take Away

This data shows that the impact of having the phone emitting vibration pulses constantly is not very high.

This means that as means to constantly convey information, e.g. as navigation system that is supposed to convey information all the time, vibration has a much lower impact on battery life compared to the screen, which empties the battery in a few hours. On a Nexus One, vibration can allow to constantly convey information for almost 24 hours, enough for the typical smartphone user who has gotten used to charge the phone every night.

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October 21, 2012November 13, 2012

NordiCHI 2012

NordiCHI is the bi-annual Nordic Conference Human-Computer Interaction. Though a country from Scandinavia traditionally hosts it, the conference attracts designers and researchers from all over the world. This year, 2012, it took place at the ITU University of Copenhagen, Denmark.

My colleague Heiko and I found this year’s NordiCHI to be an excellent forum for exchanging ideas in a super-friendly environment. We received plenty of valuable feedback for our ongoing research on using ambient light to remind office worker about upcoming tasks. In addition, there were plenty of interesting talks in up to four parallel sessions.

Highlights

Edward Cutrell et al. investigated the question of “how bad is good enough?” with respect to the quality of mobile videos. This work addresses the problem of mobile video consumption in areas where data connection is highly expensive. They therefore explored, which level of quality is still acceptable for low-income mobile-phone users in urban India. The results provide evidence that these people will accept a significant loss of quality in order to save money.

Interesting insights were that in these areas of the world, people need to “count” their bytes, which is hardly supported by today’s phones and applications. Also, Ed Cutrell suggested that the acceptance of low-quality videos depends on the user expectance. This may be relevant in developed countries, too, e.g. when people try to go online in mass events.
Anne Oeldorf-Hirsch, Jonathan Donner, Edward Cutrell : How Bad is Good Enough? Exploring Mobile Video Quality Trade-offs for Bandwidth-Constrained Consumers.

Charlotte Magnusson et al. presented Context Cards, a novel, light-weight way of raising developer’s awareness about different contexts in which mobile applications can be used. Each card shows a different setting, such as a young mother with a kid on one hand, the phone in the other, while pushing a baby buggy. They distributed the Context Cards at the Mobile World Congress, the “world’s premier mobile industry event” and received very positive feedback from attendees. Context Cards are free to use and can be accessed in printable form from here.
Charlotte Magnusson, Andreas Larsson, Anders Warell, Håkan Eftring, Per-Olof Hedvall : Bringing the mobile context into industrial design and development.

Thomas Visser, in his talk “I Heard You Were on Facebook” explored the creation of awareness systems, i.e. systems that provide a subtle sense of what is going on in one’s social network. They developed an awareness system that allows recording short sound bites from daily life and share them via Facebook. On the basis of a study with three groups of four persons each, they conclude that sharing sound bites increases the perceived social awareness of the group members.
Stefan Veen, Thomas Visser, and David V. Keyson : “I Heard You Were on Facebook” – Linking Awareness Systems to Online Social Networking.

Ole Sejer Iversen et al. presented insights from participatory design with mentally disabled users, which was done for a local art museum. They pointed out that we cannot just bring our set of values to the table but values emerge and require mediating in participatory design with diverse user groups.
Ole Sejer Iversen, Tuck W Leong – ‪Values-led Participatory Design – Mediating the Emergence of Values.

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October 18, 2012October 19, 2012

App Store Studies : How to Ask for Consent?

App Stores, such as Apple’s App Store or Google Play, provide researchers the opportunity to conduct experiments with a large number of participants. If we collect data during these experiments, it may be necessary to ask for the users’ consent beforehand. The way we ask for the users’ consent can be crucial, because nowadays people are very sensitive to data collection and potential privacy violations.

We conducted a study suggesting that a simple “Yes-No” form is the best choice for researchers.

Tested Consent Forms

We (most of the credit goes to Niels Henze for conducting the study) tested four different approaches to ask for the consent to collect non-personal data. All consent forms contain the following text:
By playing this game you participate in a study that investigates the touch performance on mobile phones. While you play we measure how you touch be we DON’T transmit personalized data. By playing you actively contribute to my PhD thesis.

Checkbox Unchecked

The first tested consent form showed an unchecked check next to a text reading “Send anonymous feedback”. In order to participate in the study a user had to tick the checkbox and then press the “Okay” button.

Checkbox Checked

The second consent form is the same as the previous one, except that the checkbox is pre-checked. To participate in the study the user has to merely click the “Okay” button.

Yes/No Button

The third consent form features two buttons are provided reading “Okay” and “Nope”. To participate the user has to click “Okay”. Clicking “Nope” will end the app immediately.

Okay Button

The foorth consent form only contains a single “Okay” Button. By clicking “Okay” the user participates in the study. To avoid participation, the user has to end the app through the phone’s “home” or “return” buttons.

Study

These consent forms were integrated into a game called Poke the Rabbit! by Niels Henze. At first start, the application randomly selected one of the four consent forms. If the use accepted to participate in the study, the app transmitted the type of the consent form to a server.

Results

We collected data from 3,934 installations. The diagram below shows the conversion rate. The conversion rate was estimated by dividing the number of participants per form by 983,5 (we assume perfect randomisation, i.e. each consent form was presented in 25% of the installations).

We were surprised about the high conversion rate. Only the consent form with the unchecked checkbox yielded in a too low conversion rate.

Conclusions – use Yes/No Buttons

We suggest using the consent form with Yes-No buttons. The consent form with the checked checkbox may considered unethical, since the user may not have read the text and was not forced to consider unchecking the checkbox. The consent form with the “Okay” button may be considered unethical, too, because users may not be aware that they can avoid data collection by using the phone’s hardware buttons. The “Yes-No” form, in contrast, forces users to think about their choice and offer a clear way to avoid participating in the study.

Yes-No buttons are ethically safe and resulted in the second highest conversion rate.

Would you suggest otherwise? We are not at all saying that this is definite! Please share your opinion (comments or mail)!

More Information

This work has been published in the position paper App Stores – How to Ask Users for their Consent? The paper was presented at the ETHICS, LOGS and VIDEOTAPE Ethics in Large Scale Trials & User Generated Content Workshop. It took place at CHI ’11: ACM CHI Conference on Human Factors in Computing Systems, which was held in May 2011 in Vancouver, Canada.

Acknowledgements

The authors are grateful to the European Commission, which has co-funded the IP HaptiMap (FP7-ICT-224675) and the NoE INTERMEDIA (FP6-IST-038419).

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